Randall Weidberg knows a bit about e-commerce. He's the founder and chief nerd at Giantnerd.com, an online store and popular social shopping hub for outdoor gear and apparel. Social shopping is a form of e-commerce where user-generated content drives the shopping experience. Founded in 2009, the Boulder, Colo.-based company tries to empower its users to work together to make educated purchasing decisions. The website gets more than 70,000 unique visitors a month and the community is made up of more than 5,000 members.

Weidberg and his employees, known affectionately as the Nerd Herd, rely heavily on social media to keep customers engaged.

"Running an e-commerce site is always a war, but the rewards far outweigh the risks," says Weidberg, who tweets at @GiantNerdCEO with mostly social shopping news and fun quips about his outdoor adventures. "Social shopping is the evolution of e-commerce."

Here's Weidberg's list of the top Twitter feeds to follow to stay on top of new and emerging trends in e-commerce:

1. @charleneliFollowers: 46,239Tweets: 2,366
Charlene Li, founder of Altimiter Group, an ecommerce research and advisory firm based in San Mateo, Calif., helps companies "leverage disruption to their advantage." She posts updates about how to take advantage of the latest ecommerce tools with a smattering of comments about her family and personal life.

Sample Tweet: Trying out @shopkick at @bestbuy. Very fun game, but ended up not buying anything - this time. Will definitely come back.

2. @GoogleRetail Followers: 13,548Tweets: 1,189
The retail group at Mountain View, Calif.-based search-engine giant Google Inc. tracks spending trends by analyzing Google searches and keeps its Twitter followers up to date on retail-industry news and data. Number-crunchers will love this feed as it's very stats-heavy.

3. @dannysullivanFollowers: 90,535Tweets: 18,807
Danny Sullivan is the Orange County, Calif.-based editor of SearchEngineLand.com, an online publication for search news, research and analysis. He tweets about Google, search-engine optimization and pay-per-click advertising.

4. @EconsultancyFollowers: 28,556Tweets: 6,077
Econsultancy.com is a London-based community for digital marketing and e-commerce professionals. The feed is helpful for learning about best practices for online marketing and e-commerce, including training and events.

5. @IR_MAGAZINEFollowers: 4,013Tweets: 825
Internet Retailer, a Chicago-based monthly publication, is an authority on e-commerce and web retailing. Its Twitter feed is best for following its headlines and reader contests.